When manufacturing an optical fiber coupler, a coated optical fiber, i.e., an optical fiber covered with a coat must be subjected to a removal of the coat at an intermediate section of the coated optical fiber. As a method of removing the coat of such a coated optical fiber, there is known a blade-using mechanical technique such as one described in Japanese Unexamined Patent Application Publication No. 2010-164697.
The coat removing method mentioned above is carried out in a state that the coated optical fiber is held with a pair of clamps and is placed on a flat base. At this time, a removal blade for removing the coat is tilted at an acute angle with respect to the coated optical fiber and is moved toward the coated optical fiber until it comes in contact with the coated optical fiber. Thereafter, the removal blade is moved in a length direction of the coated optical fiber, to bite the coat of the coated optical fiber. This is carried out until an edge of the removal blade comes in contact with an outer circumferential face of the optical fiber in the coat. Thereafter, the removal blade is moved away from the optical fiber within a thickness range of the coat. With the edge being at the front in a moving direction, the removal blade is moved in the length direction of the coated optical fiber, thereby removing the coat.